Project Summary In our recently published work, we discovered that CUB-Domain-Containing Protein 1 (CDCP1) is a new and important ligand of CD6, which is a marker and a critical regulator of T cells, demonstrating a surprising role of CDCP1 in immune regulation. CDCP1 was originally discovered to be overexpressed on certain solid tumor cells, regulating tumor-cell anoikis resistance. However, the distribution of CDCP1 in the eye and its potential role in tissue homeostasis was unknown. In our latest (unpublished) work, using CDCP1 knockout (KO) mice and CDCP1 knocked down human corneal epithelial cells, we discovered that CDCP1 is highly and selectively expressed on corneal epithelial cells among all ocular cells, and that CDCP1 is critical for enhancing corneal wounding healing. In this proposed project, using the unique reagents and models that we have developed, including CDCP1-KO mice, CD6-KO mice, CDCP1-KO human corneal epithelial cells and recombinant mutant CDCP1 proteins, we will elucidate both the intrinsic and extrinsic mechanisms by which CDCP1 enhances corneal wound healing. We will also test novel CDCP1-targeted approaches as new therapeutics for accelerating corneal wound healing. The proposed work would establish a previously unknown role of CDCP1 in corneal wound healing, facilitate the development of new and effective therapies for this corneal pathological condition, and open a new avenue for research on CDCP1 and corneal homeostasis.